The Avengers
by Canis Lupus 54
Summary: Sasuke tries something a little different in his final fight with Naruto.
1. Chapter 1

"Enough," said Sasuke, cutting off another of Naruto's speeches, "I'm the strongest there is now."

Now, how to prove it? He could absorb the chakra of the captured bijuu, or he could use Kaguya's dimension switching technique. Their eyes were similar, after all.

 _Yes, that's it,_ he thought, _I'll prove my strength by mimicking the progenitor of all chakra._

So, he tried to shift to Kaguya's gravity dimension.

Suddenly, Sasuke was surrounded by huge buildings of glass and steel in the middle of the night. Naruto was nowhere in sight. In fact, no one was anywhere in sight. Sasuke would have expected such a large city to have a lively nightlife, but there was no one around. How suspicious. Then, Sasuke sensed an attack from behind and leapt forward.

He halted and turned to see a man in blue armor crouched where Sasuke had once stood, holding a red spear embedded in the concrete beneath him. That dimension shifting technique was unexpectedly chakra draining, yet it looked like Sasuke would have to fight anyway.

"Not bad, kid," said the spearman, standing to his full height. "It takes some serious reflexes to dodge that."

Sasuke teleported to the man, dropped to the ground, and kicked upward, hitting the man square in the jaw. Following that, he leapt into the air and shadowed the spearman. Sasuke unleashed a savage combination of kicks and punches, ending with kicking the man in the stomach and punching him in the chest, driving him down into the ground. It was a little slower than he would have liked, but then it had been a while since he had performed the Lion's Barrage.

The spearman quickly recovered and stabbed at Sasuke's chest. Sasuke easily dodged the blow and aimed a chidori at the rising man's chest.

Lancer leapt back with a manic grin on his face. It appeared he had found someone pretty fun to fight. The kid had an insane amount of mana and it looked like he knew how to use it. Still, the kid was panting heavily. It looked like whatever spell had allowed him to appear out of nowhere like that was taking its toll on him.

Lancer charged at the kid.

 _I am not going to die like this,_ Sasuke thought. _I'm going to become Hokage, and bring peace to the world!_

Then, he started glowing with a bright white light and a strange circle with markings appeared on the ground in front of him. There was a blinding flash of light. When Sasuke could see again, a figure in heavy silver and red armor with a horned helmet and a sword at their hip was standing in front of him.

"Servant Avenger, accepting your summons," the figure said calmly. "I ask of you: are you my Master?"

Sasuke had no idea what was going on, but he was quick to take advantage of the opportunity that presented itself.

"Sure," he said. "Now, help me kill the spearman."

"Yes, Master."

The figure, Avenger, drew their sword and charged at the spearman.

 _Not again!_ Lancer thought as he parried Avenger's first strike. What were the odds of two potential victims summoning Servants at the exact right time, one of them being an _eighth_ Servant called Avenger?

Avenger struck again with a diagonal slash. Lancer blocked the attack and the two Servants stood with their weapons locked against each other for a moment. Then, Lancer heard a sound like many birds chirping at once from behind him. He threw himself to the side. The kid's lightning technique grazed his arm and Avenger's sword powered through Lancer's block, raking across his chest.

Lancer eyed his two opponents warily.

"Come on," he said. "This is getting good!"

 _Lancer, that's enough come back!_

"Oh, not now! Sorry, but my Master is a coward!"

Sasuke watched as the man suddenly started talking to himself, then made a lame excuse before running away. Sasuke turned to Avenger.

"Okay, now it's time to explain what's going on," he said.

"You are part of the Holy Grail War, a competition among heroes summoned as Servants and their Masters for a wish-granting artifact known as the Holy Grail. Normally there is only seven of each, but we are the eighth pair."

"Hn. Interesting. Your name is Avenger, right?"

"That is my class. Servants are divided into the classes Saber, Lancer, Archer, Lancer, Rider, Assassin, Caster, and my class, Avenger. Our classes are used as names to protect our identities."

"Because, if you know a heroes identity, you know their strengths and weaknesses."

"Precisely. We should go to the nearest Catholic Church to register as participants."

"We'll find a place to stay first, then you can tell me what a Catholic Church is."

"Okay."

Sasuke found a hotel. He used a genjutsu to pay for his stay and disguise Avenger's conspicuous. Though, apparently, his clothing was unusual here too, if the fact that he had never heard of this "cosplay" before was any indication.


	2. Chapter 2

Sasuke sat down on his hotel bed. It was hardly the most comfortable thing in the world, but Sasuke was used to worse. Sasuke had decided to take a brief rest before heading to this "Catholic Church" of which Avenger spoke. During this rest, he spoke with Avenger.

"Take off your helmet," Sasuke commanded. "I'd like to know what my Servant looks like."

Avenger obeyed, lifting her helmet off her head and placing it on the bed beside her. She had a regal face with bright green eyes, framed by short blonde hair.

"Huh, so you're a girl," said Sasuke. "At least I think so."

Avenger snarled at her Master, releasing an enormous wave of killing intent. Sasuke scowled back and countered with his own blast of killing intent. Avenger instantly calmed and cast her eyes downwards. Sasuke's counter had settled the manner, and given his neighbor's visions of their horrible deaths.

"I apologize or my outburst, Master," said Avenger. "It won't happen again. You are correct. I am female."

"Hmm. What are these markings on my hand?"

"Those are your Command Seals. You have three, and each guarantees my obedience once when used. When all three are used, our contract is void."

"Interesting. We should get you some inconspicuous clothing."

"That won't be a problem."

Avenger was enveloped in a burst of red light. When it cleared, she was dressed in a red crop top, short shorts, and a red jacket.

"That's convenient," said Sasuke. "Let's go find this church."

Sasuke and Avenger set out into the town and, after a bit of searching, found the church. Sasuke went inside alone, while Avenger waited outside. Sasuke looked around the darkened interior of the church with his Sharingan and Rinnegan active. Suddenly, he sensed someone trying to sneak up on him. Sasuke whirled around and created a Chidori Sharp Spear, holding it to the man's throat. The man regarded Sasuke with a look of feigned surprise.

"Peace, my child," said the man. "I am Kotomine Kirei. What are you here for?"

"Uchiha Sasuke. The Holy Grail War," Sasuke replied briskly.

"Ah, the eighth Master. Might I advise you that the war, and magic in general, are supposed to be a secret."

Sasuke dispersed his spear, but kept his doujutsu active. "Noted."

"You must have many questions—"

"Not really, my Servant explained everything."

"Well, then, let me give you a gift." Kotomine produced a book and handed it to Sasuke. "This book will automatically fill up with information on the Servants you fight."

Sasuke regarded the book warily, but it didn't appear to be dangerous. "Thanks."

After that, Sasuke walked out of the church. He scanned the area and saw a man wearing some strange red garments standing next to a girl wearing a red coat over a uniform of some sort in a tree. The man was aiming a bow at Sasuke, a glowing arrow nocked on it. He fired.

Sasuke easily teleported out of the arrow's way and manifested a partial Susanoo, which protected him from the arrow's explosion. Sasuke then fired back with his Susanoo's bow. The man widened his eyes and leapt out of the arrow's path, grabbing the girl with him as he went. The arrow destroyed the tree as the man landed roughly on his back on the ground.

"Who are you?" Sasuke asked the man.

"Archer," the man replied coolly as he stood.

Archer materialized twin swords, one black and one white, then charged at Sasuke, only to be cut off by the now armored Avenger. Archer leapt backwards as Avenger slashed at him.

"Master, stay back!" Avenger warned. "Servants are far stronger than humans!"

"Trust me, if you, Archer, and Lancer are any indication, I'll crush every Servant," Sasuke said calmly.

He created a chidori and ran at Archer, aiming his attack at the man's head. The man parried with one of his swords, but the chidori went right through, forcing Archer to drop to the ground to avoid it. The Servant was far from helpless, however, as he swept his legs underneath Sasuke. Sasuke easily stepped back, out of Archer's range and made the hand signs for Katon: Gokakyu no Jutsu, then breathed a fireball at Archer. Archer rolled out of the way and sprung to his feet, preparing for another charge.

Then, Avenger was on him again, slashing down at him with a powerful overhand strike. Archer raised his swords in a cross formation and blocked the blow, then kicked Avenger away. Sasuke was there in an instant, kicking Archer in the stomach, then punching him in the face, sending the Servant tumbling away.

Suddenly, pain shot through Sasuke's body. He looked at the girl to see her pointing at him, shooting projectiles from her finger. They made eye contact and the girl collapsed, trapped in a genjutsu. Sasuke refocused on Archer, who was charging again, and used Amaterasu on him. Archer screamed in pain and astralized. Sasuke could still see him just fine, but the flames suddenly went out. Archer rushed to Rin, rematerialized, picked her up, and ran.

Sasuke glared at Avenger.

"How did they know we were here?" Sasuke asked, annoyed.

"They must have sensed my summoning and waited for us here," Avenger replied.

"Well then, let's leave before more show up."

"Too late, Onii-chan!"


	3. Chapter 3

Sasuke turned to regard the source of the child-like voice. As it turned out, the source was a child, a girl no older than ten. Said child had a giant, grey skinned man wielding a weapon that was part sword, part axe, and part club, standing behind her.

"It was super cool how you handled a Servant all by yourself like that, Onii-chan!" the girl said admiringly. "It's such a shame you have to die. But before you do, I'll see your full power. Berserker, make him show me!"

The monster behind her, presumably Berserker, roared. It was a strange sound. Not quite human, not quite bestial. Others may have been intimidated. But Sasuke had faced worse. He had stood up to gods and demigods and walked away the victor. He wouldn't be cowed by a random brute.

Berserker charged at the shinobi with speed unexpected from something so big. Sasuke calmly walked forward to meet the giant.

"Master, this foe is beyond us!" Avenger shouted, taking a step back in fear.

"Beyond you, maybe," Sasuke replied coolly as lightning gathered in the palm of his left hand.

 _Chidori!_

Sasuke stabbed his hand into the giant's heart, piercing the skin with ease and destroying the organ as Berserker screamed in pain. The beast stumbled backwards before falling over, dead. Sasuke grunted dismissively at the corpse and turned to leave.

"It's not over yet, Onii-chan!" the girl shouted out to him. "Berserker is the great hero Heracles, and he as twelve lives, one for each labor he completed!"

Sasuke lazily turned back towards Berserker as the leaden giant stood and roared in rage, the wound on his chest fully healed. He raised his weapon and swung down on Sasuke, only for his attack to bounce uselessly off Sasuke's partial Susanoo. Sasuke manifested the sword and cut Berserker in half.

Once again, the "great hero" fell over dead, but the halves of his body moved toward each other and merged back together. The grey skinned titan stood and roared again. That was getting rather annoying. Sasuke readied his sword again and ignited it with black flames.

 _Enton: Susanoo Kagutsuchi!_

Sasuke swung again, this time igniting the enemy Servant. Berserker roared in agony and stumbled back, batting uselessly at the black flames and succeeding only in spreading the flames further. Soon, the flames burned the giant to death and he fell over.

Life came back into the giant's eyes shortly after, only for the flames to kill him again. This process repeated twice more, before the giant managed to stand, still wreathed in flames, and roar in anger. He started slowly towards Sasuke, clearly still in pain, as Sasuke prepared to use Kirin on Berserker.

"Berserker, astralize!" the girl shouted at her Servant. Berserker ignored her, continuing his slow advance towards Sasuke. The girl's hand glowed a bright red. "Berserker, disappear and retreat!"

Berserker grit his teeth and roared once more, then smashed his axe-sword into the ground, creating a cloud of debris. When the cloud cleared, Berserker and his Master were gone. Sasuke could have caught them, but he didn't particularly feel like it.

"Avenger, we're going back to the hotel," he said.

"Yes, Master," Avenger said.

…

"Ugh, what happened?" Rin said, holding her head in her hands. "I just had the worst dream…"

Getting stabbed for hours on end certainly qualified as a nightmare in Rin's book. She and Archer had retreated to the Emiya estate.

"The kid must have trapped you in some kind of illusion to take you out of the fight," Archer said. "With his speed, we're lucky he didn't kill you outright."

"Tell me about it," Rin replied. "It looked like even you were having trouble with him. His Servant barely did anything."

"Caught me off guard is all. Next time I'll get him for sure."

"Get who?" Emiya asked, coming into the guest house. "What happened, Tohsaka?"

"Archer and I went to investigate the eighth Master," Rin said. "Turns out he's some kind of crazy strong fighter who can keep up with Servants. He looked weird too. Long black hair and dressed in weird clothes. Wait a minute…" An idea had just occurred to Rin. Who else could keep up with Servants? "Emiya-kun, where's our newest house guest?"

"In the kitchen eating instant ramen."

"He might know something!"


	4. Chapter 4

_The previous night…_

Shirou, Rin, and Saber sat around the table eating dinner. Well, Saber was eating. Rin and Shirou had long since finished and were simply marveling at Saber's ability to keep eating. Saber finished her fifth bowl of rice and held out the empty bowl to Shirou.

"Excellent as always, Shirou," Saber said. "May I have some more?"

"Of course, Saber!" Shirou replied. "Eat as much as you like!"

A flash of light suddenly enveloped the room, blinding the inhabitants. When their vision returned to them, a teenage boy, slightly older than Shirou and Rin, with blonde hair and bright blue eyes, was standing on the table looking very confused. The room's original three inhabitants looked incredulously at the boy, who gave a nervous smile in reply.

"Um… hi," he said.

Moments later, Saber was in her battle wear, chasing the boy through the house, swinging her invisible sword at him. The boy managed to stay just out of range at all times.

"Ah! What are you doing?" the boy exclaimed.

"That's my line!" Saber replied. "Who are you, and what are you doing in this house?"

"Uzumaki Naruto, and I have no idea!"

Saber lunged forward and stabbed at the boy. He whirled around with some sort of swirling blue orb in his hand and, somehow, managed to place it right in the sword's path. The two attacks struggled against each other for a moment, before the blue orb burst, throwing the boy and Saber backwards.

"Look," Naruto said calmly. "I don't know what I'm doing here, how I got here, or even where here is. But I don't want to hurt anyone here. Just let me leave peacefully."

Saber narrowed her eyes. Then, Shirou finally caught up, panting from trying to keep pace with a Servant.

"Wait, Saber!" Shirou shouted. "I think he's telling the truth. It doesn't seem like he's from around here. Do you have anywhere to stay?"

Naruto rubbed the back of his head and laughed nervously. "Of course I… don't. But I'll figure it out, don't worry about me."

"If you don't know where you're going to stay, you can stay here for now."

"Wow, really, thanks!"

Saber shook her head and sighed. "Shirou, you are far too trusting. But I won't question your decision."

 _Present..._

"And he had this lightning technique he tried to skewer Archer with!" Rin finished explaining to Naruto.

"Some black fire too," Archer said.

Naruto slurped up a mouthful of noodles and nodded thoughtfully as he chewed. "Yeah, I know him," he said. "That's Sasuke. He's my best friend, but I doubt he'll listen to me right now. We both want peace, but he has some… interesting ideas on how to achieve that. I was trying to beat some sense into him when I ended up here. If he's here too, it might be something he did that sent us here."

"He seemed pretty strong," Rin commented.

"If that's all you saw, then Sasuke wasn't even close to taking you seriously," Naruto said seriously. "I'd suggest you stay away from him for now. I'll fight him if someone needs to."

Shirou gulped. "Taking on a Servant and he wasn't even serious?"

Saber nodded. "A difficult claim to believe. But if true, this 'Sasuke' may be the most dangerous opponent of the war. Even more so than Berserker."

Rin cupped her chin thoughtfully. "We need a plan before we can take him on again."

…

Sasuke and Avenger sat in their hotel room.

"I'm bored," Sasuke said. "I'm going out."

"It would be best to lay low to avoid fighting," Avenger suggested.

"I don't need to avoid it. Come it you want."

Sasuke stood and strode out of the room, Avenger trailing behind him shortly.


End file.
